Universal serial bus (USB) interface for mass storage device

ABSTRACT

A mass storage device motherboard or secondary board includes a bridging circuit. The bridging circuit converts signals from the mass storage device into USB signals. The bridging circuit can be provided by a chip that converts ATA/ATAPI signals into USB signals.

[0001] This application claims priority from U.S. ProvisionalApplication Serial No. 60/249,530 filed Nov. 17, 2000, the contents ofwhich are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

[0002] This invention relates generally to technologies for driving massstorage devices. More specifically, this invention relates to devicesand methods for communicating between a host motherboard and one or moremass storage devices.

[0003]FIG. 1 illustrates a conventional communications interface betweena host motherboard 10 and a mass storage device motherboard 20.Referring to FIG. 1, traditional communication between a motherboard 20of a mass storage device and a host motherboard 10 occurs via a driveinterconnection ribbon cable 15. Using this communications method, thehigh speed Integrated (or Intelligent) Drive Electronics (IDE) data andcontrol signals must generally be driven through connectors andpotentially lengthy cabling to off-board electronics.

[0004] More recently, FireWire-based mass storage devices have becomeavailable in configurations that have either an adaptor board or mainboard integration to accomplish a bridging function. These devices areclassified as bridging devices because there are still intermediateprotocols (i.e., such as ATA/ATAPI or SCSI) between the mass storagehead and the I/O connectivity leaving the mass storage devicemotherboard.

SUMMARY OF THE INVENTION

[0005] A bridging technology according to various aspects andembodiments of the present invention enables mass storage applicationsto benefit from the speed and versatility of the Universal Serial Bus(USB) protocol, and particularly USB 2.0.

[0006] According to one aspect of the present invention, a bridgingcircuit is configured to provide communication between a mass storagedevice motherboard and a USB port on a host motherboard.

[0007] According to another aspect of the present invention, a massstorage device motherboard has a bridging circuit embedded thereinAccording to yet another aspect of the present invention, a chip isprovided to convert ATA/ATAPI signals into USB signals.

[0008] A mass storage device motherboard, according to a preferredembodiment of the invention, comprises an onboard bridging circuit totranslate ATA/ATAPI signals into USB 2.0 signals. Most preferably, thebridging circuit comprises a single bridging chip. Providing translationcapabilities in a single chip simplifies the task of integrating thedrive and input/output (I/O) electronics to support USB connectivitydirectly onto the mass storage device motherboard itself. The massstorage device motherboard could be used for any mass storage device,such as hard drives, magneto optical drives, CD drives, CD-RW drives,DVD-RAM drives, DVD+RW drives, and others.

[0009] Alternatively, a secondary board could be used to provide thetranslation function. In this embodiment, the secondary board includesthe bridging circuit for converting ATA/ATAPI signals to USB signals.The secondary board receives the ATA/ATAPI signals from a mass storagedevice motherboard and outputs USB signals to the host motherboard.

[0010] According to another aspect of this invention, a bridging chip,used to provide ATA/ATAPI to USB 2.0 conversion, receives ATA/ATAPIsignal input into a disk interface through an ATA/ATAPI interface portand outputs USB signals to a USB interface through a USB transceiver.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The foregoing objects, features, and advantages of the presentinvention will become more readily apparent from the following detaileddescription of preferred embodiments, made with reference to thefollowing figures, in which:

[0012]FIG. 1 is a schematic diagram illustrating a conventionalcommunications interface between a mass storage device motherboard and ahost motherboard.

[0013]FIG. 2 is a schematic diagram illustrating a secondary board (orbridging device) for converting ATA/ATAPI signals from a mass storagedevice into USB signals, according to one embodiment of this invention.

[0014]FIG. 3 is a schematic diagram illustrating an integrated massstorage device motherboard having onboard USB communications accordingto another aspect of this invention.

[0015]FIG. 4 is a schematic diagram illustrating the construction andlayout of a bridging chip used to provide ATA/ATAPI to USB conversion inthe secondary board of FIG. 2 and the integrated mass storage devicemotherboard of FIG. 3.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0016] Referring to FIG. 2, according to one embodiment of thisinvention, a secondary board (or bridging device) 25 includes a bridgingcircuit to convert ATA/ATAPI signals from a mass storage devicemotherboard 20 into USB signals. The secondary board 25 preferablyutilizes a bridging chip 100 to provide the bridging circuit.

[0017] Referring to FIG. 3, according to another embodiment of thisinvention, an improved mass storage device motherboard 20 a has anonboard bridging circuit that provides ATA/ATAPI to USB translation. Asin the earlier embodiment, the bridging circuit is preferablyimplemented using a bridging chip 100. The bridging chip 100 readilypermits the integration of all of the drive and I/O electronics tosupport USB connectivity onto the device motherboard 20 a.

[0018] The secondary board 25 and improved mass storage devicemotherboard 20 a, according to these preferred embodiments of theinvention, can be used to facilitate more efficient communicationbetween a host motherboard and a hard drive, magneto optical drive, CDdrive, CD-RW drive, DVD-RAM drive, DVD+RW drive, or any other massstorage device or combination of mass storage devices. These and otheraspects and embodiments of the invention will be described in furtherdetail below.

[0019] In the embodiment shown in FIG. 2, a bridging chip 100 is locatedon a bridging device comprising an intermediate or secondary circuitboard 25. The bridging chip 100 translates ATA/ATAPI signals into USB2.0 signals. Use of a separate, secondary board 25 to provide thebridging function, rather than an integrated motherboard, may bedesirable, for instance, where integration onto the motherboard 20 ofthe mass storage device itself is impractical. A secondary board mayalso be desirable when retrofitting the communications interface of anexisting mass storage device.

[0020] According to this embodiment, an intermediate forty pin (orforty-four pin for a 2.5 inch drive) conductor ribbon cable 15 a havingtwo headers and two mating ribbon cable connectors is arranged betweenthe mass storage device motherboard (or primary circuit board) 20 andthe secondary (or bridging) circuit board 25. The secondary board 25receives ATA/ATAPI signals from the mass storage device through theintermediate conductor ribbon cable 15 a. The secondary board 25includes the bridging chip 100 for converting the ATA/ATAPI signals intoUSB 2.0 signals. The USB 2.0 signals are then supplied to the hostmotherboard (not shown) through a USB connector 35.

[0021] Referring to FIG. 3, according to another aspect of thisinvention, the USB interface is integrated directly onto the massstorage device motherboard 20 a using the bridging chip 100. Provisionof the ATA/ATAPI to USB 2.0 conversion function in a single chip 100simplifies this integration. Onboard conversion to the USB protocolallows optimization of the drive characteristics with respect to thesignals that were conventionally required to go to the driveinterconnect ribbon cable 15 (see FIG. 1). Onboard bridging circuitintegration thereby lowers the power requirements of the mass storagedevice by eliminating the need to drive the high speed IDE data andcontrol signals through connectors and potentially lengthy cabling tooff-board electronics.

[0022] Referring to FIGS. 2 and 3, the integration of the bridgingcircuit directly onto the mass storage device motherboard 20 a alsoprovides improvements over the bridging device 25 of FIG. 2. Among otherthings, permitting the ATA/ATAPI signals to remain on the primarycircuit board 20 a eliminates the need for an intermediate conductorribbon cable 15 a and its headers, and further eliminates the need formating ribbon cable connectors on the primary and secondary circuitboards 20, 25.

[0023] Another benefit of this integrated configuration over theearlier-described embodiment is the elimination of duplicate resourcesthat are otherwise required on each separate circuit board 20, 25. Theseresources include, but are not limited to, reset logic, power supplyswitching, regulation and conditioning, clock generation circuitry, andcrystal(s) for clock generation. Duplicate power supply cabling andtheir associated connectors can also be eliminated, provided that themass storage device can be powered from the USB bus directly or bycurrent augmentation, such as that described in U.S. Pat. No. 6,252,375,the contents of which are incorporated herein by reference in theirentirety.

[0024] Additional advantages of this embodiment include the eliminationof the secondary circuit board 25 and the associated hardware used tomount and secure the secondary board 25 and to support its connectorsand cables. The components needed to reduce EMI emissions from theconnecting or power supply cables are also eliminated. The noisesusceptibility of the mass storage device is also reduced because of theelimination of its cables and connectors. These benefits, individuallyand collectively, further result in lower production costs, a reducedoverall parts count, and increased reliability of the mass storagedevice.

[0025] The USB technology itself also offers several advantages overother communications technologies. One advantage is that the currentthrough the USB wiring is relatively low compared to that of othertechnologies. USB also enables plug-and-play capabilities, where othertechnologies require manual adjustment of dip-switch settings and thelike. Furthermore, USB-connected devices can be powered from the USB busor through current augmentation, whereas devices using othertechnologies are typically powered through their own, independent powersupplies.

[0026] Referring to FIG. 4, a single-chip, application-specificintegrated circuit (ASIC) 100 preferably performs the ATA/ATAPI to USB2.0 translation function in the secondary board 25 of FIG. 2 as well asin the integrated mass storage device motherboard 20 a of FIG. 3. Thischip 100, called the ISD300, has an integrated USB 2.0 physicalinterface transceiver (PHY) 130, Serial Interface Engine (SIE) 125, DataBuffering, and Disk Interface (DISK_INT) 115. The bridging chip 100receives data into an input 110 thereof, performs the conversionfunction, and outputs a USB signal from an output 135 thereof.

[0027] More specifically, an ATA/ATAPI Interface serves as an input 110to receive ATA/ATAPI signals from a read unit of the mass storage device(not shown). The Disk Interface (DISK_INT) 115 receives the ATA/ATAPIsignals from the ATA/ATAPI Interface 110 and transmits them the othercomponents. The remaining chip components provide conversion logic andare used to buffer and convert the ATA/ATAPI signals into USB 2.0signals. The resulting USB signals are output to a USB Interface 135through the USB 2.0 physical interface transceiver (PHY) 130.

[0028] The ISD300 can perform the translation function without requiringany firmware within the chip. The translation is accomplished using astate-machine that can perform the translation function without any coderunning inside of it. The ISD300 can be configured to receive directionfrom the hard drive, such as embedded control information, that tellsthe chip what to do with the information once it has passed through thetranslation bridge.

[0029] Having described and illustrated the principles of the inventionwith respect to various preferred embodiments thereof, it should beapparent that the invention can be modified in arrangement and detailwithout departing from such principles. We therefore claim allmodifications and variations coming within the spirit and scope of thefollowing claims.

What is claimed is:
 1. A method of communicating with a mass storagedevice, comprising: receiving ATA/ATAPI signals from a mass storagedevice into a bridging circuit; converting the ATA/ATAPI signals fromthe mass storage device into USB signals using the bridging circuit; andoutputting the USB signals from the bridging circuit.
 2. A methodaccording to claim 1, wherein the bridging circuit is provided in asingle, bridging chip.
 3. A method according to claim 1, wherein thebridging circuit is provided on a motherboard of the mass storagedevice.
 4. A method according to claim 1, wherein the bridging circuitis provided on a secondary board.
 5. A method according to claim 4,wherein a mass storage device motherboard outputs ATA/ATAPI signals, andwherein the secondary board receives the ATA/ATAPI signals from the massstorage device motherboard and converts them into USB signals.
 6. Amotherboard for a mass storage device, said motherboard comprising:input logic configured to receive an input signal from a read unit ofthe mass storage device; a bridging circuit configured to receive theinput signal from the input logic and convert the input signal into aUSB signal; and output circuitry configured to output the USB signalfrom the motherboard.
 7. A mass storage device motherboard according toclaim 6, wherein the bridging circuit comprises a bridging chip forconverting the input signal into the USB signal.
 8. A mass storagedevice motherboard according to claim 6, wherein the bridging chipcomprises: an ATA/ATAPI interface configured to receive ATA/ATAPIsignals from the input logic; a disk interface configured to receiveATA/ATAPI signals from the ATA/ATAPI interface; a serial interfaceengine; and a USB physical interface transceiver configured to receivesignals from the serial interface engine and output USB signals to a USBinterface.
 9. A secondary board configured to enable communicationbetween a mass storage device motherboard and a host motherboard, saidsecondary board comprising: a connector port for receiving signals fromthe mass storage device motherboard; a bridging circuit for convertingsignals from the mass storage device motherboard into USB signals; and aUSB connector port for outputting the USB signals to the hostmotherboard.
 10. A secondary board according to claim 9, wherein thebridging circuit comprises a bridging chip configured to translate thesignals from the mass storage device motherboard into USB signals.
 11. Asecondary board according to claim 10, wherein the bridging chipcomprises a USB physical interface transceiver, a serial interfaceengine, and a disk interface.
 12. A secondary board according to claim11, wherein the disk interface receives ATA/ATAPI signals through anATA/ATAPI interface, and wherein the ATA/ATAPI signals are convertedinto USB 2.0 signals and are output to a USB Interface through the USBphysical interface transceiver.
 13. A bridging chip comprising: an inputconfigured to receive ATA/ATAPI signals; conversion logic configured toconvert the ATA/ATAPI signals into USB signals; and an output configuredto output the USB signals.
 14. A chip according to claim 13, whereinsaid input comprises an ATA/ATAPI interface arranged to receive theATA/ATAPI signals and a disk interface configured to receive ATA/ATAPIsignals from the ATA/ATAPI interface; wherein said conversion logiccomprises a serial interface engine and a USB physical interfacetransceiver, said interface transceiver being configured to receivesignals from the serial interface engine and output USB signals to a USBinterface.
 15. A chip according to claim 13, wherein the chip is locatedon a mass storage device motherboard.
 16. A chip according to claim 13,wherein the chip is located on a secondary board.
 17. A chip accordingto claim 16, wherein the secondary board is arranged to receiveATA/ATAPI signals from a motherboard of the mass storage device.
 18. Amethod of converting signals from a mass storage device into USBsignals, said method comprising: receiving a signal from a mass storagedevice into a bridging chip; converting the signal from the mass storagedevice into a USB signal; outputting the USB signal from the bridgingchip.
 19. A method of converting signals according to claim 18, whereinsaid bridging chip is located on a motherboard of the mass storagedevice.
 20. A method of converting signals according to claim 18,wherein the bridging chip is located on a secondary board arranged incommunication with a motherboard of the mass storage device.